Class FeatureCollectionIteration


  • public class FeatureCollectionIteration
    extends Object
    The FeatureCollectionIteration provides a depth first traversal of a SimpleFeatureCollection which will call the provided call-back Handler. Because of the complex nature of Features, which may have other Features (or even a collection of Features) as attributes, the handler is repsonsible for maintaining its own state as to where in the traversal it is recieving events from. Many handlers will not need to worry about state.

    Implementation Notes: The depth first visitation is implemented through recursion. The limits to recursion depending on the settings in the JVM, but some tests show a 2 argument recursive having a limit of ~50000 method calls with a stack size of 512k (the standard setting).

    Author:
    Ian Schneider, USDA-ARS, Chris Holmes, TOPP
    • Constructor Detail

      • FeatureCollectionIteration

        public FeatureCollectionIteration​(FeatureCollectionIteration.Handler handler,
                                          FeatureCollection<?,​?> collection)
                                   throws NullPointerException
        Create a new FeatureCollectionIteration with the given handler and collection.
        Parameters:
        handler - The handler to perform operations on this iteration.
        collection - The collection to iterate over.
        Throws:
        NullPointerException - If handler or collection are null.
    • Method Detail

      • iteration

        public static void iteration​(FeatureCollectionIteration.Handler handler,
                                     FeatureCollection<?,​?> collection)
        A convienience method for obtaining a new iteration and calling iterate.
        Parameters:
        handler - The handler to perform operations on this iteration.
        collection - The collection to iterate over.
      • iterate

        public void iterate()
        Start the iteration.
      • walker

        protected void walker​(FeatureCollection<?,​?> collection)
        Perform the iterative behavior on the given collection. This will alert the handler with a handleFeatureCollection call, followed by an iterate(), followed by a handler.endFeatureCollection() call.
        Parameters:
        collection - The collection to iterate upon.
      • iterate

        protected void iterate​(FeatureIterator<?> iterator)
        Perform the actual iteration on the Iterator which is provided.
        Parameters:
        iterator - The Iterator to iterate upon.
      • walker

        protected void walker​(Feature feature)
        Perform the visitation of an individual Feature.
        Parameters:
        feature - The Feature to explore.